Animal Unit Month (AUM)
The amount of forage needed to sustain one cow, five sheep, or five goats for a month
Livestock Grazing in the UFO
Currently 628,754 acres (93%) of BLM-administered public land within the Uncompahgre Field Office are allocated for livestock grazing. The public range is permitted at a level of 43,491 AUMs of forage. This figure includes 38,200 active AUMs and 5,291 AUMs of suspended use. Permittees paid to use 29,219 AUMs of forage in 2008.
Over the past five years, billed use has averaged 65% of total permitted use. This difference can be attributed to a number of variables. Seasonal variations in precipitation and temperature result in more or less available forage from one year to the next. Drought conditions have required a reduction in grazing use in order to maintain good range conditions. Permittees may also opt for voluntary non-use for a variety of reasons, resulting in AUMs that are available but not used. In addition, grazing is typically deferred in an area for two years following land treatments and fire rehabilitation projects, accounting for lower use levels.
There are 46,923 acres (7%) of BLM-administered public land within the UFO not allocated for livestock use. In addition, a small number of permits have been voluntarily relinquished and the allotments are considered vacant.
Within the UFO, there are 203 allotments and 135 permittees. Allotments vary in size from 40 to 92,198 acres, with grazing allocations ranging from one to 4,800 AUMs in each allotment. In 2009, 85% of the allotment permits were for cattle, with sheep and horse grazing accounting for the remaining 15%. Individual operators graze animals on 188 allotments, while the remaining fifteen are common allotments grazed by two or more operators.
Grazing within the UFO occurs throughout the year, with much of the use concentrated during spring and fall months. Spring and fall allotments are typically located adjacent to U.S. Forest Service land, and are utilized for short periods prior to “on” dates and after “off” dates for higher elevation summer allotments on national forest land. Summer use allotments are commonly found at higher elevations in the North Fork of the Gunnison River area. Winter use allotments are primarily located in the west end of Montrose and San Miguel Counties, at lower elevations associated with a semi-arid climate.
Controlling Noxious Weeds in the UFO
Integrated Weed Management (IWM)
The use of all suitable weed control methods to keep weed populations below the economic and ecological injury level
Preventing the introduction of noxious and invasive species is the first line of defense against noxious weed establishment. The UFO applies Integrated Weed Management principles and Early Detection/Rapid Response strategies to curtail damage to ecosystems by noxious weeds.
IWM utilizes a combination of control strategies which will hopefully result in the most effective control of target noxious species. IWM methods include cultural practices, use of biological, physical, and the selective use of herbicides. Following the use of control measures, monitoring is conducted to determine which treatments are working, and on which species.
Early detection and rapid response efforts increase the likelihood that invasions will be addressed successfully while populations are still localized and population levels are not beyond that which can be contained and eradicated. Once populations are widely established, all that might be possible is the partial mitigation of negative impacts. In addition, the costs associated with such efforts are typically far less than those of long-term invasive species management programs.
Surveying for noxious species is important and is focused on high-priority targets, such as high-risk locations, high-value resources, important pathways, and populations and species of specific concern. More remote backcountry areas are also surveyed and monitored, although at longer intervals.